The present invention relates, most generally, to optoelectronic telecommunications systems. More particularly, the present invention relates to an enclosure for housing optical subassemblies and associated components.
Optoelectronic devices such as vertical cavity surface emitting lasers (VCSELs) and other lasers, photodiodes and other photodetectors, have become widely used in the telecommunications and other industries. In optoelectronic devices, an electrical signal is converted to an optical signal that travels along a transmission medium such as an optical fiber and is then typically converted back to an electrical signal. A high optical coupling efficiency ensures good optoelectronic connections. The electrical-to-optical optoelectronic connections are typically made in optical subassemblies (OSAs) such as TOSAs (transmission OSAs) and ROSAs (receiving OSAs). The optoelectronic devices and the connection of the optical transmission media to the optoelectronic devices are typically delicate, and therefore an OSA having stable mechanical support as well as a high quality optical connection, helps ensure a high optical coupling efficiency.
The optoelectronic devices commonly used in today""s telecommunication industry typically operate at high frequencies such as 2.5-10 GBPS (gigabits per second) and higher. Therefore, when an OSA and the associated high frequency components are joined to a customer board or other mother board which contains low frequency components, it is desirable to suppress EMI (electromagnetic interference) noise from adversely affecting other portions of the module circuitry such as circuitry operating at other frequencies. Optoelectronic devices, and the various OSAs which contain them, are typically included in an enclosure or housing that contains various other electronic components and is joined to the customer board or other mother board. The housing may be configured to be mounted over further electronic components mounted on the customer board.
The present invention provides a housing for housing optoelectronic components such as TOSAs and ROSAs, printed circuit boards, and the like. The housing is suitable for various optoelectronic devices. In one exemplary embodiment, the housing is a multiple-piece housing which, according to one exemplary embodiment of the invention, includes an internal septum that suppresses high frequency noise such as EMI and RFI from traveling between the chambers of the housing.
According to another embodiment of the invention, the housing includes a peripheral engaging feature including a groove, a gasket, and a tongue that is received within the groove and compresses the gasket. The peripheral engaging feature may be used to suppress high frequency noise such as EMI and RFI. According to another exemplary embodiment, the present invention provides a channel having a cross-sectional area that varies intermittently along the longitudinal direction. The corrugated channel retains a gasket and allows for an improved and continuously tight seal to be formed between the components which combine to form the multiple-piece housing.
According to another exemplary embodiment, the housing of the present invention includes an opening through its bottom surface. The housing is mounted on a mounting surface such that components formed on the mounting surface are nested within the housing. The bottom of the housing includes a recessed portion having a bowed surface and a gasket received within the recessed portion. The gasket combines with the bowed recessed portion to form a tight seal between the housing and the mounting surface. The tight seal is capable of suppressing EMI and RFI noise.
According to another exemplary embodiment, the housing of the present invention includes internal grounding leads which contact relief features of the conductive housing and direct internal errant signals to the internal grounding strips and eventually the intended ground path.
According to another exemplary embodiment, the present invention includes an opaque housing having an internal portion and an external portion and a bottom surface having an opening therethrough. The opening through the bottom is bounded by beveled edges that aid in the blind alignment of the housing over components formed on the mounting surface.
According to yet another exemplary embodiment, the housing further includes means for alleviating axial strain on optical fibers extending from the housing and optically coupled to optoelectronic devices within the housing. The present invention provides arms that extend from the housing and retain optical fibers. The optical fiber is joined to the arm by means of an adhesive. Axial strain at the optical connection is alleviated because the optical fiber is affixed to the housing at a point external to the optical connection, and therefore no strain is exerted at the optical coupling point and the optical coupling efficiency is not compromised. A pocket formed in the arm of the enclosure contains the adhesive which bonds the optical fiber to the enclosure arm.